Ovivo Mobile, a virtual operator in the UK that offered a free mobile services in exchange for serving advertising, has closed down abruptly due to “reasons beyond our control.”

A notice on the company’s website — first spotted by the BBC — announces that the service shut down on March 19 with no prior warning. Although it doesn’t elaborate on the reasons behind its shuttering, it does provide a way for users to port their number to another mobile network.

Ovivo users were provided with a free SIM and mobile services in return for making themselves available for targeted advertising. A CIOL article from February suggested that the company had over 50,000 subscribers in the UK — its only market — and that it was looking to raise £3 million ($5 million) in order to expand overseas in 2015.